The Drosophila genetic locus pecanex, when mutated, gives a Notch-like embryonic hyperneuralization phenotype, as a maternal effect. In order to understand how this gene functions in the differentiation of the embryonic nervous system, a detailed molecular analysis has been undertaken. Already pecanex has been localized at the genomic DNA level and its transcript has been identified. During the award period, further work will focus on two goals: isolation and nucleotide sequence analysis of cDNA clones complementary to the transcript, and use of these clones to produce antisera directed against the pecanex protein product. The immunogens for antiserum production will be either synthetic peptides predicted from portions of the cDNA sequence, or fusion proteins produced by recloning of cDNA inserts into E. coli expression vectors. The antisera thus produced will be used for in vivo localization of the protein by indirect immunofluorescence, and for experiments in which phenocopies of pecanex will be induced in wild-type embryos; ultimately, I hope to use them for affinity purification of the protein.